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Security Advisory

USN-4692-1: tar vulnerabilities




Canonical Ubuntu

Versions Affected

  • Canonical Ubuntu 14.04
  • Canonical Ubuntu 16.04
  • Canonical Ubuntu 18.04


Chris Siebenmann discovered that tar incorrectly handled extracting files resized during extraction when invoked with the –sparse flag. An attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 12.04 ESM, Ubuntu 14.04 ESM, Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2018-20482)

Daniel Axtens discovered that tar incorrectly handled certain malformed tar files. If a user or automated system were tricked into processing a specially crafted tar archive, a remote attacker could use this issue to cause tar to crash, resulting in a denial of service. (CVE-2019-9923)

CVEs contained in this USN include: CVE-2018-20482, CVE-2019-9923.

Affected Cloud Foundry Products and Versions

Severity is low unless otherwise noted.

  • cflinuxfs3
    • All versions prior to 0.221.0
  • Xenial Stemcells
    • 456.x versions prior to 456.133
    • 621.x versions prior to 621.97
    • All other stemcells not listed.
  • CF Deployment
    • All versions prior to 16.0.0


Users of affected products are strongly encouraged to follow the mitigations below. The Cloud Foundry project recommends upgrading the following releases:

  • cflinuxfs3
    • Upgrade All versions to 0.221.0 or greater
  • Xenial Stemcells
    • Upgrade 456.x versions to 456.133 or greater
    • Upgrade 621.x versions to 621.97 or greater
    • All other stemcells should be upgraded to the latest version available on
  • CF Deployment
    • Upgrade All versions to 16.0.0 or greater


2021-02-10: Initial vulnerability report published.

Cloud Foundry Foundation Security Team Profile Image

Cloud Foundry Foundation Security Team, AUTHOR